
# 用任意语言实现逆序输出一个字符串
# str1 = '北京欢迎你'
# str2 = str1[::-1]
# print(str2)

# str = 'a,hello'在字符串str中查找hello
# str2 = str[1]
# print(str2)




numbers = [1, 5, 3, 9, 7]
numbers.sort(reverse=True)
print(numbers)
